Evidence for Climate Change

Climate Change throughout History

To determine if the world’s temperature is increasing, several different methods are used, including data, where data exists, historical documents, glacier activity, sediment, tree rings, ice cores, corals, and carbon fourteen dating (Botkin & Keller, 2013). I will talk about only a couple of these. One way that scientist’s used to discovering the past climate and compare its changes throughout history, that I found interesting, is the use of historical documents.

Researchers can use historical documents such as paintings to reconstruct the climate. For example, “ships logs from the Spanish, Dutch, and English ships crossing the world’s oceans between the sixteenth and twentieth centuries, provide insight into weather patterns and how these change over time” (Oosthoek, 2015, pp. 1, pp.1). Another example, “is the painting of glaciers in the Swiss Alps, in some paintings the glaciers reached down into the valley below, indicating cold times, and in some painting the glaciers were high up in the mountains, showing warm eras” (Botkin & Keller, 2013, p. 482, pp. 1). Several other historical documents are used to include, “people’s written recollections in books, newspapers, journal articles, personal journals, ships’ logs, travelers’ diaries, and farmers’ records, along with dates of wine harvests and small grain crops” (Botkin & Keller, 2013, p. 482, pp. 1).

Another method I found interesting was how scientists use tree rings to determine how the climate has changed over the centuries. Since the growth of trees is affected by the climate, the tree rings that trees develop over the years can tell scientists a lot about the atmosphere of that tree’s life (Botkin & Keller, 2013). When the tree rings are broad, it means climate conditions were suitable for growth; when the tree rings are narrow, it means climate conditions were not good for growth (Botkin & Keller, 2013).

The Greenhouse Effect

The greenhouse effect is the natural process by which the Earth’s atmosphere traps gases and warms the Earth, most is caused by water vapor (Botkin & Keller, 2013). It is called the greenhouse effect because the gases trapped in the atmosphere act like the window panes of a greenhouse, reflecting that warmth back to the surface of the Earth(Botkin & Keller, 2013). The natural gases in the Earth’s atmosphere, such as carbon dioxide and methane, provide a protective layer of gases from the Sun’s energy. Without that protective layer, the Sun could strike the Earth. Greenhouse gases catch the sun’s rays and reflect some of that warmth back to Earth warming the temperature (Botkin & Keller, 2013). However, human activity has increased the number of greenhouse gases in the atmosphere past natural conditions, causing Earth’s temperature to rise to never before seen temperatures (Botkin & Keller, 2013).

Greenhouse Gases

Carbon dioxide is a greenhouse gas that traps heat in the atmosphere, contributing to global warming and is emitted into the atmosphere naturally. However, human activity has increased the amount of carbon dioxide in the atmosphere to 396 parts per million (ppm), an increase of over a hundred ppm since the Industrial Revolution (Botkin & Keller, 2013).

Methane is a greenhouse gas that contributes to global warming by trapping heat in the atmosphere. Methane is naturally created by certain bacteria’s that live in oxygenless environments, such as the intestines of certain mammals. However, the emittance of methane into the atmosphere over the last two hundred years as increased due to human activity. “Humans contribute methane into the environment by landfills, the burning of biofuels, the production of coal and natural gas, and agriculture” (Botkin & Keller, 2013, p. 494, pp. 3).

“Chlorofluorocarbons (CFC’s) are stable, inert compounds that are used in aerosol cans and refrigerators” (Botkin & Keller, 2013, p. 494, pp. 4). Scientists estimate “that 15% to 25% of the anthropogenic greenhouse effect may be related to CFCs” (Botkin & Keller, 2013, p. 494, pp. 4). The use of CFC was banned by the US government in 1978, which is a good thing because CFCs have the ability to absorb thousands of times more infrared radiation than carbon dioxide (Botkin & Keller, 2013).

Nitrous oxide contributes as much as five percent of greenhouse gases to the greenhouse effect. Human activity contributes this greenhouse gas into the atmosphere by using fertilizers in agricultural activities and by the burning of fossil fuels. Nitrous oxide stays in the environment for several decades (Botkin & Keller, 2013).

Evidence for Global Climate Change

Sea levels rise because of two contributing factors, the melting of land glaciers and the expansion of water. As the atmosphere warms up, much of that extra heat is taken in by our oceans and seas, causing the water to expand (NASA, 2015). Evidence shows that the global sea level has risen 6.7 inches in the last century and with the melting of land glaciers, that number is only going to increase. The rising of global sea levels has already affected some island nations, including the Marshal Islands, whose residents are living in the ocean now, and scientists predict that by the year 2050 seventeen percent of Bangladesh may be underwater (Davenport, 2015).

Impact of Climate Change in the Great Plains

I live in South Dakota, which is a part of the great plains of the United States. The great plains stretch across the United States from the border of Canada to the border of Texas and consists of a variety of environments and ecosystems. The effects of climate change on the great plains is many and varied (Environmental Protection Agency, 2015). As winters get warmer, crop cycles will alter requiring new techniques for farmers to grow their crops. The increase in global temperatures will increase the chance of droughts stressing the High Plains Aquifer, where most of the great plains get their water. With droughts will come changes in the water availability, causing challenges to crop irrigation and threatening wetlands (Environmental Protection Agency, 2015). Wetlands help to purify water naturally and are important in many respects. Climate change will impact the great plains in many ways, most of those ways will affect the United States food chain, to include the production of meat, and dairy (Environmental Protection Agency, 2015).